Technical Field
The present disclosure relates to an optical image capturing system. More particularly, the present disclosure relates to a compact optical image capturing system applicable to electronic products.
Description of Related Art
In recent years, with the popularity of mobile products having camera functionalities, the demand of miniaturized photographing systems has been increasing. The sensor of a conventional photographing system is typically a CCD (Charge-Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor) sensor. As the advanced semiconductor manufacturing technologies have allowed the pixel size of sensors to be reduced and compact photographing systems have gradually evolved toward the field of higher megapixels, there is an increasing demand for compact photographing systems featuring better image quality.
A conventional photographing system employed in a portable electronic product mainly adopts a four-element lens structure or a five-element lens structure such as the ones disclosed in the U.S. Pat. No. 7,869,142 and the U.S. Pat. No. 8,000,031. Due to the popularity of mobile products with high-end specifications, such as smart phones and PDAs (Personal Digital Assistants), the requirements for high resolution and image quality of present compact photographing systems increase significantly. However, the conventional photographing system cannot satisfy these requirements of the compact photographing systems.
Other conventional compact photographing systems with six-element lens structure such as the one disclosed in the U.S. Publication No. 2012/0314304 A1 enhance image quality and resolution. However, the shape of the object-side surface of the fifth lens element cannot effectively control the angle at which the incident light projects onto an image sensor from every field. Therefore, this photographing system tends to produce more spherical aberration, coma aberration and astigmatism which will influence image quality.